This invention relates generally to electrical switches and, more particularly to electrical switches of the snap action type such as are used with a float bulb to operate a sump pump.
Broadly speaking, such switches have long been known and used in the prior art. See, for example, U.S. Pat. No. 4,196,325 issued to S. A. Povilaitis on Apr. 1, 1980 and U. S. Pat. No. 4,916,274 issued to R. H. Hawley et al. On Apr. 10, 1990. A problem encountered with these prior art switches is in assembling their components by hand within the depression formed in the switch housing and in maintaining a cooperative relationship between the assembled components until a cover can be applied to the housing to hold such components in proper operating position relative to one another.
In such a switch, an electrically insulated U-shaped bridge support, which carries a pair of electrically conductive contact bridges on parallel extending, spaced apart arms thereof, is switched between a closed position, wherein the bridges contact fixed wire lead terminals, and an open position, wherein the bridges break contact with the terminals. The switching occurs due to rocking movement of an elongated actuator arm or operating lever which has a pair of transversely projecting, cylindrically shaped ears which are seated in a pair of vertically extending and upwardly opening slots formed in interior walls of the housing. A forward end of the operating lever is rounded so as to fit within a semi-spherical depression in a pivot bushing mounted on one end of a coiled actuator spring. The other end of the actuator spring fits around a tab located in the center of a cross member of the bridge support. The spring is thus held in compression between the rounded end of the operating lever and the cross-member of the bridge support such that, when the operating lever is actuated to rock the rounded end thereof toward the housing cover, the cross-member is moved by the spring in the opposite direction to close the contact bridges against the fixed wire lead terminals. Conversely, when the operating lever is actuated to rock the rounded end toward the upper surface of the housing, the spring forces the cross member to move in the opposite direction toward the cover to disengage the contact bridges from the wire lead terminals.
A difficulty encountered with this type of prior art switch is in assembling the spring, with its pivot bushing on the spring end opposite the rounded end of the operating lever, placing the other end of the spring around the tab on the cross member of the support bridge, and then placing the operating lever in the housing so that its ears are pressed against the bases of the corresponding slots while, at the same time, holding the rounded end of the operating lever against the pivot bushing in the spring. Failure to successfully accomplish this relatively complex maneuver will result in failure to place these parts in the necessary cooperative relationship with one another. Another difficulty encountered with such a switch is in holding these parts in the proper cooperative relationship until the cover is properly placed on the housing to maintain the required relationship
By means of my invention, these and the other difficulties encountered using prior art snap action switches are substantially overcome.